Thermoelectric device

ABSTRACT

A thermoelectric device includes a thermoelectric element module arranged such that the vertically upper side is the cooling side and the vertically lower side is the heating side. On the cooling side of the thermoelectric element module, a DC-DC converter, a cooler, and a heat-transfer grease layer are arranged in this order from the vertically upper side.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a thermoelectric device that cools an electronic device using a temperature difference created by the Peltier effect of a thermoelectric element.

2. Description of Related Art

In order to promote efficient use of the heat in vehicles, installation of thermoelectric devices, which use phenomena that associate the heat of thermoelectric elements with electricity such as the Seebeck effect, the Peltier effect and the Tomson effect, in the vehicles has been considered.

Japanese Patent Application Publication No. 2005-51952 (JP-A-2005-51952) describes an example of the above-described thermoelectric devices. The thermoelectric device described in JP-A-2005-51952 generates electricity by converting the heat of exhaust gas into electricity using the Seebeck effect of a thermoelectric element. The thermoelectric device is structured such that a heating portion of a thermoelectric element module, a cooling portion of the thermoelectric element module, a water-cooling cooler that cools the cooling portion of the thermoelectric element, and a DC-DC converter that converts an output of the thermoelectric element into electricity are arranged in this order from an exhaust pipe.

In order to reduce the contact thermal resistance between the exhaust pipe and the cooler, and the thermoelectric element module, grease layers (heat-transfer grease layers) may be provided between the exhaust pipe and the cooler, and the thermoelectric element module. If air enters the heat-transfer grease layers, the heat resistance increases, resulting in a reduction of the efficiency of the thermoelectric device. Accordingly, air is expelled from the heat-transfer grease layers by applying pressure through tightening of a bolt. In this way, an increase in the heat resistance is suppressed. However, in order to apply pressure through tightening of a bolt, it is necessary to perform a work for tightening the bolt during installation of the thermoelectric device, resulting in a reduction of the installation efficiency.

SUMMARY OF THE INVENTION

The invention provides a thermoelectric device in which entrance of air into a heat-transfer grease layer is suppressed without tightening of a bolt.

A first aspect of the invention relates to a thermoelectric device. The thermoelectric device includes a thermoelectric element arranged such that the vertically upper side is the cooling side and the vertically lower side is the heating side. On the cooling side of the thermoelectric element, an electronic device that is an object to be cooled, a cooler, and a first heat-transfer grease layer are arranged in this order from the vertically upper side.

With the structure described above, pressure is applied to the first heat-transfer grease layer under the weight of the electronic device. Therefore, it is possible to suppress entrance of air into the first heat-transfer grease layer without performing tightening of a bolt.

The electronic device may be a DC-DC converter. Other examples of the electronic device may include any in-vehicle electronic devices that need to be cooled. The DC-DC converter may be a converter that adjusts the drive voltage for driving the thermoelectric element.

In the thermoelectric device, on the heating side of the thermoelectric element, a second heat-transfer grease layer, a heater, and a heat-insulating layer are arranged in this order from the vertically upper side.

A second aspect of the invention relates to a thermoelectric device. The thermoelectric device includes: an electronic device; a cooler that cools the electronic device; a first grease layer; and a thermoelectric element that is arranged such that the vertically upper side of the thermoelectric element is the cooling side and the vertically lower side of the thermoelectric element is the heating side. In the thermoelectric device, the electronic device, the cooler, the first grease layer, and the thermoelectric element are arranged in this order from the vertically upper side toward the vertically lower side.

The thermoelectric device may further include: a second grease layer; a heater that is heated by the thermoelectric element via the second grease layer; and a heat-insulating layer. In the thermoelectric device, the thermoelectric element, the second grease layer, the heater, and the heat-insulating layer are arranged in this order from the vertically upper side toward the vertically lower side.

A third aspect of the invention relates to a thermoelectric air-conditioner for a vehicle. The thermoelectric air-conditioner includes the thermoelectric device according to the first or second aspect of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Features, advantages, and technical and industrial significance of exemplary embodiments of the invention will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein:

FIG. 1 is a view schematically showing the overall structure of a thermoelectric air-conditioner to which a thermoelectric device according to an embodiment of the invention is applied;

FIG. 2 is a perspective view showing the exploded perspective structure of the thermoelectric device according to the embodiment;

FIG. 3 is a perspective view showing the perspective structure of the thermoelectric device according to the embodiment;

FIG. 4 is a sectional view showing the side sectional structure of a thermoelectric element module and portions near the thermoelectric element module of the thermoelectric device according to the embodiment; and

FIG. 5 is a sectional view showing the side sectional structure of the thermoelectric element module of the thermoelectric device according to the embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereafter, a thermoelectric device according to an embodiment of the invention will be described in detail with reference to FIG. 1 to FIG. 5.

A thermoelectric device 1 according to the embodiment is provided in a vehicle thermoelectric air-conditioner as shown in FIG. 1. The thermoelectric device 1 includes, as a main component, a thermoelectric element module 2 that creates a temperature difference using the Peltier effect of a thermoelectric element (Peltier element). The thermoelectric element module 2 is arranged such that the vertically upper side thereof is the cooling side and the vertically lower side thereof is the heating side. A cooler 3 through which the cooling medium flows is arranged on the vertically upper side (cooling side) of the thermoelectric element module 2, and a DC-DC converter 4 that adjusts the drive voltage for driving the thermoelectric element module 2 is arranged on the cooler 3. A heater 5 through which the heating medium flows is arranged on the vertically lower side (heating side) of the thermoelectric element module 2.

The cooler 3 constitutes a cooling medium circulation pathway through which the cooling medium is circulated between the cooler 3 and a radiator 6 that radiates the heat of the cooling medium into the outside air. The heater 5 constitutes a heating medium circulation pathway through which the heating medium is circulated between the heater 5 and a heater core 7 that warms the air that is supplied into a vehicle compartment, using the heat of the heating medium.

As shown in the exploded perspective structure in FIG. 2, on the vertically upper side (cooling side) of the thermoelectric element module 2 of the thermoelectric device 1, the DC-DC converter 4, the cooler 3, and a heat-transfer grease layer 8 are arranged in this order from the vertically upper side in the vertical direction. In addition, on the vertically lower side (heating side) of the thermoelectric element module 2, a heat-transfer grease layer 9, the heater 5, and a heat-insulating layer 10 are arranged in this order from the vertically upper side in the vertical direction. The thermoelectric device 1 as shown in FIG. 3 is formed by stacking these elements on top of another in the above-described order.

As shown in FIG. 4, the thermoelectric element module 2 is sandwiched between the cooler 3 and the heater 5 with the heat-transfer grease layer 8 interposed between the thermoelectric element module 2 and the cooler 3 and with the heat-transfer grease layer 9 interposed between the thermoelectric element module 2 and the heater 5. As shown in the side sectional structure of the thermoelectric element module 2 in FIG. 5, a p-type semiconductor 11 p and a n-type semiconductor 11 n, which constitute the thermoelectric element (Pertier element) of the thermoelectric element module 2, are connected at the vertically upper side (cooling side) thereof to an electrode 14 provided on an insulating substrate 13, via solder 12. Further, the p-type semiconductor 11 p and the n-type semiconductor 11 n are connected at the vertically lower side (heating side) thereof to an electrode 17 provided on an insulating substrate 16, via solder 15.

Next, the operation of the thus structured thermoelectric device will be described. The cooler 3 through which the cooling medium constantly flows is arranged at the cooling side of the thermoelectric device 1. The DC-DC converter 4 provided on the top face of the cooler 3 is cooled by the cooling medium.

The thermoelectric device 1 is driven by the drive voltage adjusted by the DC-DC converter 4, and creates a temperature difference between the cooling side and the heating side. More specifically, in the thermoelectric device 1, the heat absorbed from the cooling medium flowing through the cooler 3 at the cooling side of the thermoelectric device 1 is transferred to the heating side of the thermoelectric device 1. Thus, the thermoelectric device 1 heats the heating medium flowing through the heater 5 arranged at the heating side of the thermoelectric device 1. The thus heated heating medium is supplied to the heater core 7, and the heat of the heating medium is used to warm the vehicle compartment.

The thermoelectric device according to the embodiment produces the following effects.

1) In the thermoelectric device 1 according to the embodiment, the thermoelectric element module 2 is arranged such that the vertically upper side thereof is the cooling side and the vertically lower side thereof is the heating side. On the cooling side of the thermoelectric element module 2, the DC-DC converter 4, the cooler 3, and the heat-transfer grease layer 8 are arranged in this order from the vertically upper side in the vertical direction. In addition, on the heating side of the thermoelectric element module 2, the heat-transfer grease layer 9, the heater 5 and the heat-insulating layer 10 are arranged in this order from the vertically upper side in the vertical direction. In the thermoelectric device 1 according to the embodiment, pressure is applied to the heat-transfer grease layers 8 and 9 under the weight of the DC-DC converter 4. Therefore, it is possible to suppress entrance of air into the heat-transfer grease layers 8 and 9 without tightening of a bolt.

2) In the thermoelectric device 1 according to the embodiment, the cooling medium constantly flows through the cooler 3 provided on the cooling side of the thermoelectric element module 2, and the DC-DC converter 4 is arranged on the top face of the cooler 3. Therefore, it is possible to perform cooling of the DC-DC converter 4 in conjunction with heat-exchange for air-conditioning of the vehicle compartment.

3) In the embodiment, because part of the heat lost from the DC-DC converter 4 is absorbed by the thermoelectric element module 2, the cooling capacity required of the radiator 6 may be reduced accordingly. Therefore, the size of the radiator 6 may be reduced.

4) In the embodiment, the thermoelectric element module 2 and the DC-DC converter 4 are located close to each other. Therefore, the length of a wire is reduced, and the electric loss is reduced accordingly.

The above-described embodiment may be modified as follows. In the embodiment described above, on the heating side of the thermoelectric element module 2, the heat-transfer grease layer 9, the heater 5, and the heat-insulating layer 10 are arranged in this order from the vertically upper side in the vertical direction. However, the arrangement of the elements and layers on the heating side of the thermoelectric element module 2 is not limited to this, and may be changed as needed. As long as, the DC-DC converter 4, the cooler 3, and the heat-transfer grease layer 8 are arranged, on the cooling side of the thermoelectric element module 2, in this order from the vertically upper side in the vertical direction, it is possible to apply pressure to the heat-transfer grease layer 8 under the weight of the DC-DC converter 4, thereby suppressing entrance of air into the grease layer 8.

In the embodiment described above, as an electronic device that is an object to be cooled, the DC-DC converter 4 that adjusts the drive voltage for driving the thermoelectric element module 2 is provided. However, the invention may be applied to structures in which electronic devices other than a DC-DC converter, for example, an inverter for a motor, which adjusts the drive voltage for driving the motor, are provided as electronic devices that are objects to be cooled.

In the above-described embodiment, the thermoelectric device according to the invention is used in a thermoelectric air-conditioner for a vehicle. However, the thermoelectric device according to the invention may be adapted to other uses. 

What is claimed is: 1-5. (canceled)
 6. A thermoelectric device, comprising: an electronic device; a cooler that cools the electronic device; a first grease layer; and a thermoelectric element that is arranged such that a vertically upper side of the thermoelectric element is a cooling side and a vertically lower side of the thermoelectric element is a heating side, wherein the electronic device, the cooler, the first grease layer, and the thermoelectric element are arranged in this order from the vertically upper side toward the vertically lower side.
 7. The thermoelectric device according to claim 6, further comprising: a second grease layer; a heater that is heated by the thermoelectric element via the second grease layer; and a heat-insulating layer, wherein the thermoelectric element, the second grease layer, the heater, and the heat-insulating layer are arranged in this order from the vertically upper side toward the vertically lower side.
 8. A thermoelectric air-conditioner for a vehicle, comprising the thermoelectric device according to claim
 6. 9. The thermoelectric device according to claim 6, wherein the electronic device is a DC-DC converter.
 10. The thermoelectric device according to claim 9, wherein the DC-DC converter adjusts drive voltage for driving the thermoelectric element.
 11. The thermoelectric device according to claim 6, wherein the electronic device is an inverter for a motor, which adjusts drive voltage for driving the motor. 